The major function of the biostatistics and radiobiological modeling core is to provide basic scientific support to all projects in terms of any study design or redesign which may be necessary as well as analysis of all project studies. The latter will be conducted on two levels; one in accordance with the usual analytic principles of controlled clinical trials to compare the treatment and control groups (e.g., the ICH guidelines- International Conference on Harmonisation, 1999); the other using radiobiological modeling in order to estimate the relevant parameters. A second function of the core is to refine and implement up-to-date methods of Phase I and II trial designs, tailored specifically to radiation therapy study applications. A third function of the core is to catalog and examine the radiobiological models appropriate for normal tissue complication and local control rates subsequent to tomotherapy and to propose appropriate designs of regimens for the clinical studies. One of the strengths of the biostatistics/medical physics/radiotherapy collaboration at UW is the involvement models of appropriate for normal tissue complication and local control rates subsequent to tomotherapy and to propose designs of regimens for the clinical studies. One of the strengths of the biostatistics/medical physics/radiotherapy collaboration at UW is the involvement of specialists from all three disciplines at all scientific stages, from the initial design of a project to its completion. The expertise available in the UW Clinical Center Bioinformatics Shared Resource and the Medical Informatics Shared Resource, along with graduate students and postdoctoral fellows and colleagues front the Departments of Statistics and Medical Physics, provides for a rich and comprehensive research environment. This not only supports objectives of individual projects but often yields discoveries and methods beyond the original goals.